Fuel filter kindly i want to know how frequently to change fuel diesel filter fuel diesel of peugeot 206 1.4 hdi 2005

There is no need to change it frequently. If there is a loss of engine power or if throttle cuts out then may be its the time to change fuel filter. It is recommended by peugeot to change fuel filter (but depends on fuel purity) after every 36000 miles.

You can clean it yourself
Dipp the whole filter body in carosine oil tank and leave it in there for about 20-30 minutes
Pour some petrol in filter with the help of plastic piped and apply a slight air pressure (use a piece of pipe to blow) in the reverse direction (marked with arrows) of fuel supply to clear residue and heavy oil composite that clogged in filter.
Repeating the cleaning process 2-3 times will clean the filter to reuse it without the need of a new one to buy.

Hello ortensja,maybe this article can help you,How to Replace Fuel Filter.

I change mine on my ford truck evert other oil change.